(1) Field of the Invention
This invention relates to a mechanical seal suitable for use in a shaft sealing section of a rotary machine, such as a centrifugal compressor, pump, etc., which is driven under high speed or high pressure condition.
(2) Description of the Prior Art
One type of mechanical seal of the prior art used in a shaft sealing section of a rotary machine comprises a rotary sealing element usually mounted on a rotary shaft for rotation therewith, a retainer secured in a seal box surrounding the rotary shaft, a sealing element held by the retainer, and resilient means for urging one sealing element against the other sealing element for providing a slidingly sealed surface between the two sealing elements. In this type of mechanical seal, difficulties are encountered in attaching and detaching the mechanical seal, particularly in handling the stationary sealing element and the retainer for holding same, because these parts must be attached to or detached from a space in the seal box surrounding the rotary shaft which is relatively small. When the seal box has a particularly small space, manual handling of these parts by the operator is faced with great difficulties. A mechanical seal of improved construction that facilitates the operation of attaching and detaching same is described in U.S. Pat. No. 4,039,196.
In recent years, mechanical seals are used under the condition of high speed or high pressure. It is essential that mechanical seals include parts formed of materials capable of withstanding such condition and constructed in a manner to be able to withstand such condition. This entails an increase in the weight of the mechanical seal as a whole which makes it necessary to use means, other than that which is disclosed in U.S. Pat. No. 4,039,196, for further providing improvements in an operation for attaching and detaching the mechanical seal to the shaft sealing section of a rotary machine. Also, in view of the high pressure and high speed conditions under which mechanical seals are required to operate nowadays, it is necessary that means be provided for effectively dissipating heat produced on the slidingly sealed surface of the mechanical seal.